Cooking creates undesirable by-products, such as heat, steam, grease, odors, and by-products of gas combustion used to heat the appliances. These cooking by-products pollute the air in a home or commercial environment if they are not safely removed. These cooking by-products are irritating, harmful and potentially hazardous. Accordingly, a multitude of ventilation systems have been developed to draw the cooking by-products away from the immediate vicinity of the cooking area and to expel this contaminated air to an external environment through an exhaust duct.
The heat generated from cooking expands the air in the cooking area and it rises, carrying with it the cooking by-products. Typical ventilation systems use a hood placed above the cooking area to capture the by-products prior to removal by a blower system. The hood is like a small room wherein too much airflow is as harmful as too little. If too much air is removed from a well insulated building, a negative pressure results rendering the ventilation system ineffective unless expensive make-up air is introduced. This can be a waste of heated or air conditioned air which must be replaced by heating and air conditioning systems. Most current systems have angular interior surfaces which do not adequately direct air flow, resulting in a large necessary amount of airflow through kitchen ventilation hoods to adequately remove offending substances and a waste of conditioned kitchen air. This resulting inefficiency increases the owner's utility bills and needlessly wastes energy. These deficiencies constitute a technical problem to be solved.